Mat forming apparatus



1961 H. E. ERICKSON ETAL 3,003,197

MAT FORMING APPARATUS 3 Sheets-Sheet 1 Original Filed May 14, 1956 INVENTORS Harold E. E r1" ckson y Rober'f' WHilgy' D le L, Schuber'l' w Oct. 10, 1961 H. E. ERICKSON ETAL 3,003,197

MAT FORMING APPARATUS Original Filed May 14, 1956 3 Sheets-:Sheet 2 INVENTORS 74 Harold E.Em'ckson BY Rober-l' TM Riley Fi 5 Dczle Lschuberf' Oct. 10, 1961 H. E. ERICKSON ET AL 3,003,197

MAT FORMING APPARATUS 3 Sheets-Sheet 3 Original Filed May 14, 1956 INVENTORS Harold EErickson y Rober'i' WRJ'IQH Dale Ltz 'huber'i United States Patent M 3,003,197 MAT FORMING APPARATUS Harold E. Erickson, Auburn, Robert W. Riley, Milton, and Dale L. Schubert, Tacoma, Wash., assignors, by direct and mesne assignments, of one-half to said Dale Luschubert, and one-half to Industrial Development Co., Tacoma, Wash., a corporation of Washington Continuation of application Ser. No. 584,677, May 14, 1956. This application Feb. 7, 1958, Ser. No. 713,9 11 Claims. (Cl. 19-156) This invention pertains to apparatus for forming solid particles into a uniform mat which thereafter may be consolidated into a product of uniform thickness and density.

I This application is a continuation of application Serial No. 584,677, filed May 14, 1956 for Mat Forming Apparatus, now abandoned.

In making consolidated products such as hardboard and other pressed fiberboards, it is common practice to reduce wood, cane, straw and other lignocellulose to small particles. These are formed dry or moist into a mat which thereafter is transferred to a hot press and consolidated to the desired density and thickness.

In these operations control of the uniformity of the mat is of primary importance in determining the uniformity of the pressed product. If the mat is non-uniform, "the pressed product will he of non-uniform density and accordingly may not meet the standards for products of this class. Control of the uniformity of the mat is difi'icult of accomplishment, however, because of the irregularity in size and shape of its component particles and their tendency to aggregate into clumps or fiocs.

Accordingly it is the general object of this invention to provide apparatus for forming solid particles into uniform mats which thereafter may be pressed into consolidated products of uniform :density.

It is another object of this invention to provide apparatus for forming uniform mats from wood chips or granular wood particles.

It is still another object of this invention to provide high capacity apparatus for forming solid particles, particularly wood chips and granules, continuously into mats suitable for pressing into fiberboard of uniform properties.

It is another object of the invention to provide mat forming apparatus which may be used to build up uniform mats from particles of widely variable identity, composition, moisture content, and size.

The manner in which the foregoing and other objects of this invention are accomplished will be apparent from the following specification and claims considered together with the drawings wherein like numerals of reference indicate like parts, and wherein:

FIG. 1 is a view in side elevation of the herein described mat forming apparatus;

FIG. 2 is a view in front elevation of the apparatus "of FIG. 1;

.' .FIG. 3 is a detail sectional view taken along line 33 of FIG. 2 and illustrating particularly the manner in :which the particles are built up on a vacuum drum into a primary deposit which thereafter is dispersed and formed into the final mat; and a against the outer surface of the drum Where they are held by the vacuum and built up into a deposit.

Means are further provided forrremoving the deposit "from the drum, after which it is passed onto dispersing "means. The dispersing means separate the component Patented Oct. 10, 1961 particles of the deposit and pass them onto a supporting surface where they are built up into a mat which is substantially free from docs and clumps. The mat thereafter may be leveled and hot pressed into a consolidated product of uniform density and thickness.

Considering the foregoing in greater detail and with particular reference to the drawings:

Solid materials in particle form, particularly wood chips and granules, are introduced into the apparatus by means of an endless, upwardly inclined conveyor 10, the upper end of which passes over drive pulley 12 on shaft 13. The conveyor preferably has on its outer surface a plurality of transverse channel-shaped members 14 providing a plurality of individual receptacles. The surface of the bed of particles contained in these receptacles is leveled by means of a leveling roll to so that as they pass over pulley 12 and become inverted, a relatively uniform feed is introduced continuously into the apparatus.

From conveyor llli the particles pass into the upper end of a vertical chute 20 over which the terminal portion of the conveyor extends. Chute 20 may be generally rectangular in cross section. It is open at its lower end for feeding the particles onto a drum assembly 30. This assembly preferably is offset from chute 26 so that particles are deposited only on a selected segment of its peripheral surface, for example, the right hand segment as viewed in FIG. 3.

Drum 319 is supported on a stationary shaft 32. It is comprised of a rotatable forarninous cylinder 33 and stationary end plates 34 which are rigid to the shaft. A vacuum conduit 36 extends through one of the end plates.

Along its inner marginal surfaces cylinder 33 has a pair of bearing members 38 which engage the edges of end plates 34 and rotatably support the cylinder. A sprocket 40 is attached to one end of the cylinder for engagement with a suitable drive for rotating the cylinder about central shaft 32.

Means are present for directing the vacuum within the drum so that it is applied to a given section only. Hence rigidly affixed to shaft 32 are a first dividing plate 42 and a second dividing plate 44. Plate 42 defines the trailing end of the evacuated section of the drum, with respect to the direction of rotation of the latter, and may be substantially alined with a side wall of chute 20. Plate 44 defines the leading end of the evacuated section of the drum and may be at any desired angle with respect to plate 42 depending upon how extensively vacuum is to be applied to the drum surface. In the illustrated embodiment, plate 44 is substantially in the seven oclock position relative to plate 42 so that vacuum is applied to a little more than half of the drum surface.

To enable its adjustment, plate 44 is mounted on a fragmentary sleeve 46 which is formed with annular slots. Bolts 48 penetrate the slots and are threaded into shaft 32 so that the angular position of plate 44 may be varied as desired. Hence there is formed within the drum a chamber defined by cylinder 33, plate 42 and plate 44. Vacuum line 36 communicates with this chamber.

As a consequence, an air stream is established through chute 2d, through the openings in cylinder 33, and through vacuum line 36. Solid particles gravitating downwardly through the chute are entrained in the air stream and drawn against cylinder 33 where they are filtered out and held in position as the cylinder rotates. Furthermore, the particles of least weight, which are carried most readily by the air stream are drawn preferentially against the freshly exposed surface of cylinder 33 just downstream from plate 42, since the air stream is of greatest intensity there.

Still further, the particles are deposited with substantial uniformity because as the openings of the drum are closed progressively .by accumulations of the particles,

3 the air stream passes preferentially through the openings which remain uncovered or are less heavily covered. As a result, particles will be deposited in these openings preferentially. This effect is of marked valuein building up a uniform deposit on the peripheral surface of the drum.

To make the deposit on the drum still more uniform, there is provided a brushing roll 50 spaced apart a desired distance from the outer surface of the drum. Rotating in the indicated direction, roll 50 removes material from the drum surface and deposits it on an endless belt 52. The belt in turn conveys the material away, and may cycle it back to conveyor for re-introduction into the apparatus.

The particles deposited on the working surface of drum 30 next are separated therefrom and transferred to dispersing means for dispersing them and depositing them on a supporting surface. In the illustrated form of the inventiton, the particles are separated from the drum by releasing the vacuum. As the surface areas of cylinder 33 pass successively to a location where vacuum no longer is applied, for example, to the left of plate 44 as viewed in FIG. 3, the particles are released and fall downwardly into a chamber defined by side wall members 54. Since the deposit on the drum is substantially uniform, a continuous and substantially uniform flow of particles thus is provided.

For dispersing the released particles an oscillating shaker 60 is stationed beneath the drum at the lower end of the chamber formed by the side walls 54. The shaker may assume a diversity of configurations but in the illustrated and preferred configuration, it includes a frame suspended from the frame of the apparatus by means of pivotally mounted rods 62, 64. Connecting rods 66 then connect the frame to an eccentric 68 driven by motor 69.

A plurality of substantially horizontal plates 70 offset from each other both horizontally and vertically in a stepped pyramidal arrangement are mountetd on the shaker frame. If desired, their upper surfaces may be provided with a plurality of spaced, angularly arranged baffies 72. In aggregate, the plates and baffies form a double cascade down both sides of which the particles tumble after being introduced on the top plate from drum 30. As the particles tumble over and between the plates, they are separated from each other and distributed uniformly. Accordingly they fall in a uniform flow onto a suitable support member.

Where the particles are to be employed in the manufacture of fiberboard by a continuous process, the support member may comprise an endless belt 74 which carlies a plurality of abutting caul plates 76. A mat 78 thus is built up on the plates. if desirable or necessary, the mat may be leveled by suitable means, for example, by means of leveling roll 80. Material removed from the mat by this roll may be conveyed to storage by vacuum conduit 82 or cycled again into the forming apparatus. The caul plates with their superimposed mat sections then may be separated from each other, introduced into a hot press, and consolidated.

The drive for the various units of the herein described apparatus is illustrated particularly in FIGS. 1 and 2. A motor 84 drives belt 86 which passes over idler pulley 88, drive pulley 9i), and drive pulley 92. Drive pulley 9%) drives leveling roll 16 by means of which the contents of receptacles 14 on conveyor -10 are leveled. Pul ley 92 is rigid to a shaft 94 to which a second pulley 96 is also keyed. Pulley 96 drives belt 98 which in turn drives roll 50 for levehng off the particles deposited on the foraminous drum 30.

A second motor 160 drives chain 162 which in turn engages a sprocket 104 on shaft 13. Rigid to this shaft is a pulley 106 by means of which feed conveyor 10 is driven.

Also rigid to drive shaft 13 is a sprocket 108 which 4 is engaged by a chain 110. The latter chain in turn engages sprocket 112 on shaft 114. Another chain 116 engages sprocket 118 on shaft 114. It passes about idler sprocket 120 and thence about "gear 40 on cylinder 33, thereby rotating the latter.

Operation The operation of the presently described mat forming apparatus is as follows: Wood chips or other solid parcles are introduced into the apparatus by conveyor 10 which passes a substantially uniform, metered flow of the particles into chute 20. The particles fall on the offset rotatable, foraminous cylinder 33 impinging upon the air evacuated portion thereof as determined by the setting of plates 42, 44 (FIG. 3).; The light particles are drawn preferentially to the portion of the cylinder just entering the chute and the low places in the particle deposit are filled automatically since the particles follow the flow of air which, in turn follows the course of least resistance.

The deposit on the cylinder is shaved by means of leveling roll 50 so that it is substantially uniform in thickness. As it passes plate '44, the vacuum is released and the particles fall upon the oscillating shaker 60. Thereupon they are agitated and separated from each other as they cascade downwardly over vertically and horizontally offset plates 70, arranged in stepped relationship on the shaker frame.

The dispersed particles pass over and between the plates and are deposited on an endless belt 74 hearing caul plates 75. This builds up on the caul plates a continuous mat, the surface of which may be shaved by roll 80. The resulting caul plates and superimposed mat sections then may be separated and introduced into a hot press for consolidation of the mat.

In this manner there is provided a mat forming apparatus which effectively produces a mat of uniform thickness and density even when using as a raw material wood chips or other solid particles which have irregular dimensions and which tend to clump and floc together. Furthermore, the apparatus is readily adaptable for "use in continuous operation in mills of high capacity.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of our invention or the scope of the subjoined claims.

Having thus described our invention, we claim:

1. Mat forming apparatus comprising a rotary foraminous drum having openings smaller than the particles to be matted, means for evacuating a longitudinal segment of the drum, means for directing a flow of solid particles against the outer surface of the evacuated segment of the drum, thereby building up a deposit of the particles thereon, the particles being released from the drum at the leading end of the evacuated segment, dispersing means positioned adjacent said leading end of the evacuated segment for receiving the deposit and for separating it substantially into its component particles, and a support member positioned for receiving the particles from the dispersing means, thereby building up a mat thereon.

2. The mat forming apparatus of claim 1 wherein the means for directing a flow of solid particles against the outer surface of the evacuated segment of the drum comprises a chute positioned above said evacuated segment of the drum and communicating therewith.

3. The mat forming apparatus of claim 2 wherein the chute is offset horizontally from the vertical center line of the drum and encloses at least a portion of the evacuated segment of the drum.

4. The mat forming apparatus of claim 1 including shaving means positioned adjacent the evacuated segment of the drum for removing particles from the surface of the deposit on the drum, thereby forming a deposit of uniform thickness thereon.

5. The mat forming apparatus of claim 1 wherein the dispersing means comprises an oscillating shaker stationed beneath the drum for receiving the deposit of particles released therefrom.

6. The mat forming apparatus of claim 5 wherein the oscillating shaker comprises a plurality of plates offset from each other vertically and horizontally to form a cascade down which the particles tumble.

7. The mat forming apparatus of claim 1 including mat leveling means positioned for removing particles from the surface of the mat on the supporting member, thereby forming a mat of uniform thickness thereon.

8. Mat forming apparatus comprising an oscillating shaker comprising a plurality of spaced substantially horizontal plates offset from each other vertically and horizontally, means for introducing a flow of solid particles onto the shaker, the particles cascading downwardly over the plates and thereby being separated and dispersed, and a conveyor stationed beneath the shaker for receiving the dispersed particles therefrom.

9. Mat forming apparatus comprising conveying means for conveying a flow of solid particles, a substantially vertically arranged chute positioned for receiving the particles, a foraminous drum having openings smaller than the particles to be matted and mounted for rotation beneath the chute but offset from the vertical center line thereof, means for evacuating that portion of the drum which lies beneath the chute, thereby forming a deposit of the particles thereon, a shaving roll positioned adjacent the evacuated portion of the drum for removing particles from the surface of the deposit on the drum, thereby forming a deposit of uniform thickness thereon, said uniform deposit of particles dropping from the drum as it passes the leading end of the evacuated portion thereof, an oscillating shaker comprising a plurality of stepped horizontal plates stationed beneath the leading end of the evacuated portion of the drum for receiving and dispering the particles released therefrom, and conveying means beneath the shaker for receiving thereon the particles dispersed thereby, thereby building up a mat of substantially uniform thickness and density.

10. Mat forming apparatus comprising a frame, means for mounting the frame for reciprocable movement, a plurality of spaced apart horizontal plates mounted on the frame and oflset horizontally and vertically from each other in a stepped arrangement, means for feeding particles to the top plate, the particles upon reciprocation of the frame cascading downwardly over and between the plates and being discharged therefrom in a dispersed stream, and a supporting member placed for receiving the stream, thereby building up a mat of particles thereon.

11. The apparatus of claim 10 wherein the plates have angularly arranged batfle means on their upper surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 1,280,863 Saunders Oct. 8, 1918 1,461,337 Weiss July 10, 1923 1,508,973 Hudson Sept. 16, 1924 1,812,108 McCullough June 30, 1931 1,907,046 Darrah May 5, 1933 2,012,250 Rundell Aug. 20, 1935 2,023,273 Laguillon Dec. 3, 1935 2,447,161 Coghill Aug. 17, 1948 2,635,301 Schubert et a1 Apr. 21, 1953 2,687,363 Manning Aug. 24, 1954 2,689,597 Kinnear Sept. 21, 1954 2,693,619 Goss Nov. 9, 1954 2,743,758 Uschmann May 1, 1956 2,744,848 Mottet May 8, 1956 2,753,598 Slayter July 10, 1956 

